Layered pressure homogenizing soft medium for li-ion rechargeable batteries

ABSTRACT

A battery cell having a layered pressure homogenizing soft medium for liquid/solid state Li-ion rechargeable batteries. The battery cell of the present technology includes one or more battery pouches, a pressure mechanism external to the battery pouches that applies a pressure to the battery pouches, and a layered pressure homogenizing soft medium that is displaced between the battery pouches and the pressure mechanism. By using a number of pressure homogenizing medium layers, each with a specific range of thickness and within a range of physical properties, the battery pouches displaced between the pressure homogenizing medium layers are evenly pressurized by the mediums due to pressure applied by the pressure mechanism to within a desired range of pressure. The pressure applied to the battery pouches by the pressure homogenizing medium is monitored by a pressure sensor, such as a two-dimensional pressure sensor. If the pressure to the battery pouches is not within a desired pressure range, a controller can control the pressure mechanism to adjust the pressure to the mediums and battery pouches to bring the pressure within the desired range.

SUMMARY

The present technology, roughly described, includes a battery cellhaving a layered pressure homogenizing soft medium for liquid/solidstate Li-ion rechargeable batteries. The battery cell of the presenttechnology includes one or more battery pouches, a pressure mechanismexternal to the battery pouches that applies a pressure to the batterypouches, and a layered pressure homogenizing soft medium that isdisplaced between the battery pouches and the pressure mechanism. Byusing a number of pressure homogenizing medium layers, each with aspecific range of thickness and within a range of physical properties,the battery pouches displaced between the pressure homogenizing mediumlayers are evenly pressurized by the mediums due to pressure applied bythe pressure mechanism to within a desired range of pressure. Thepressure applied to the battery pouches by the pressure homogenizingmedium is monitored by a pressure sensor, such as a two-dimensionalpressure sensor. If the pressure to the battery pouches is not within adesired pressure range, a controller can control the pressure mechanismto adjust the pressure to the mediums and battery pouches to bring thepressure within the desired range.

In embodiments, a lithium-ion battery cell can include one or morepressure homogenizing medium layers. The lithium-ion battery cell caninclude a battery casing, one or more lithium ion pouches, a first planejig and a second plane jig, a pressure sensor, and one or more pressurehomogenizing medium layers. The one or more lithium ion pouches can bedisplaced adjacent to each other within the battery casing. The firstplane jig can be displaced at a first end of the one or more lithium ionpouches and the second plane jig can be displaced at a second end of theone or more lithium ion pouches. The pressure sensor can be displacedbetween the first plane jig and the second plane jig, and can detect apressure applied to the one or more lithium ion pouches. The pressureapplied to the one or more lithium ion pouches can be adjusted based onthe detected pressure. The one or more pressure homogenizing mediumlayers can be displaced between first plane jig and the second planejig.

In embodiments, a method for maintaining a homogenous pressure onbattery pouches of a lithium-ion battery cell includes applying aninitial pressure to one or more lithium ion battery pouches containedwithin a battery cell. The battery cell can include a first plane jigand a second plane jig, a pressure sensor, and one or more pressurehomogenizing medium layers. The first plane jig can be positioned near afirst end of the one or more lithium ion pouches and the second planejig can be positioned near a second end of the one or more lithium ionpouches. The pressure sensor can be displaced between the first planejig and the second plane jig within the battery cell. The one or morepressure homogenizing medium layers can be displaced between first planejig and the second plane jig. The method also includes detecting apressure to the one or more lithium ion battery pouches by the pressuresensor, and automatically adjusting the pressure applied to the lithiumion battery pouches by a pressure mechanism based on the detectedpressure.

BRIEF DESCRIPTION OF FIGURES

FIG. 1A is a block diagram of a battery system with a stand-alonecontroller.

FIG. 1B is a block diagram of a battery system with a controllerimplemented within a battery management system.

FIG. 2 is a block diagram of a pouch cell battery.

FIG. 3 is a block diagram of a pouch cell battery with a layeredpressure homogenizer medium.

FIG. 4A is a block diagram of a pouch cell battery with a single layerpressure homogenizer medium.

FIG. 4B is an illustration of a pouch cell pressure pattern for thesingle-layer pressure homogenizer medium.

FIG. 5A is a block diagram of a pouch cell battery with a double layerpressure homogenizer medium.

FIG. 5B is an illustration of a pouch cell pressure pattern for thedouble-layer pressure homogenizer medium.

FIG. 6A is a block diagram of a pouch cell battery with a triple layerpressure homogenizer medium.

FIG. 6B is an illustration of a pouch cell pressure pattern for thetriple-layer pressure homogenizer medium.

FIG. 7 is an exemplary method for pressurizing a pouch cell battery.

FIG. 8 is a table with exemplary parameters for pressure homogenizermedium layers within a pouch cell battery.

FIG. 9 is a computing environment for use with the present technology.

DETAILED DESCRIPTION

The present technology includes a battery cell having a layered pressurehomogenizing soft medium for liquid/solid state Li-ion rechargeablebatteries. The battery cell of the present technology includes one ormore battery pouches, a pressure mechanism external to the batterypouches that applies a pressure to the battery pouches, and a layeredpressure homogenizing soft medium that is displaced between the batterypouches and the pressure mechanism. By using a number of pressurehomogenizing medium layers, each with a specific range of thickness andwithin a range of physical properties, the battery pouches displacedbetween the pressure homogenizing medium layers are evenly pressurizedby the mediums due to pressure applied by the pressure mechanism towithin a desired range of pressure. The pressure applied to the batterypouches by the pressure homogenizing medium is monitored by a pressuresensor, such as a two-dimensional pressure sensor. If the pressure tothe battery pouches is not within a desired pressure range, a controllercan control the pressure mechanism to adjust the pressure to the mediumsand battery pouches to bring the pressure within the desired range.

For both solid and liquid state secondary batteries (SSB), use ofLi-metal is significantly attractive since it exhibits very high energydensity. However, it typically shows very poor cyclability and safetyresilience due to formation of dendrite. One of the primary causes ofthe dendrite formation is inhomogeneity of current density to theelectrode. The present technology provides a solution toward theinhomogeneity by using an external pressure monitoring and homogenizingsolution. In particular, external modules—external to the batterypouches themselves—of the present technology physically homogenize theinternal pressure of the electrode and, consequently, provide forimproved and more uniform electrode current density through the batterypouches of the battery cell.

Lithium battery cells that incorporate pouch cells receive force fromthe outside casing. Unlike prior battery cells that utilize cylindricalor winding cells, lithium pouch cells are liquid electrolyte cells.Rather, lithium ion pouch cells are steady state battery cells, and arecharacterized as having better chemistry and a different design thatcylindrical or winding lithium ion battery cells that utilize liquidelectrolyte. One aspect of lithium ion pouch cells is that they need aconstant pressure in order to minimize dendrite and have uniform currentdensity. Use of pressure homogenizing medium layers provide for a moreeven pressure distribution across the surface of pouch cells, therebyminimizing dendrite and providing a more uniform current density.

FIG. 1 is a block diagram of a battery system with a stand-alonepressure controller. System 100 of FIG. 1 includes load 110, batterymanagement system (BMS) 120, battery cell 140, and pressure controller150. Battery cell 140 may provide a potential across load 110. Batterycell 140 may include one or more pouch cells, pressure homogenizingmedium layers, a pressure mechanism 132, and pressure sensor 130.Pressure sensor 130 can detect the pressure applied by pressuremechanism, for example metal plates on opposing sides of the pouch cellsand pressure homogenizing medium layers. BMS 120 may receive pressurereadings from pressure sensor 130 and communicate with pressurecontroller 150 to apply pressure to the pouch cells from the metalplates.

FIG. 1B is a block diagram of a battery system with a controllerimplemented within a battery management system 105. The battery systemof FIG. 1B has similar components to the system of FIG. 1A except thatsystem 105 has a pressure controller 155 implemented within BMS 120. Inthe implementation of FIG. 1B, the BMS implemented controller may detectthe pressure value from pressure sensor 130 and adjust the pressureapplied to battery pouches and one or more pressure homogenizing mediumlayers of the battery cell 140. In this manner, BMS 120 may maintain adesired pressure between the pouch cells of battery cell 140 bycontrolling pressure controller 155 based on readings from pressuresensor 130.

FIG. 2 is a block diagram of a pouch cell battery. Pouch cell battery200 of FIG. 2 includes pressure mechanism components such as metal planejigs 220 and 224 and pressure alignment screws 240 and 242. Pouch cellbattery also includes pouch cells 210, 212, 214. The pouch cells may bepositioned adjacent to each other, for example such that the flatsurface of the pouch is facing a flat surface of an adjacent pouch, andmay have terminals 230, 232, and 234, respectively, to provide chargefrom each pouch.

The pouch cells may operate in a more desirable manner when a certainpressure is applied to the pouch cells. As a result, the metal planejigs 220 and 222 may be configured to apply a pressure to the pouchcells via pressure alignment screws 240 and 242. In some instances, apressure mechanisms may include pressure alignment screws, motors todrive the metal plane jigs towards each other or away from each otheralong the screws, and other components typically used in an externalpressure mechanism designed to apply a pressure to the pouch cells (and,as illustrated in FIG. 3, pressure homogenizing medium layers).

FIG. 3 is a block diagram of a pouch cell battery with pressurehomogenizer medium layers. The pouch cell battery 300 of FIG. 3 includespouch cells 310-314, a pressure mechanism, and one or more pressurehomogenizer medium layers 320. The pressure mechanism includescomponents such as pressure alignment screws 343 42, metal plane jigs330-332, and pressure mechanism motor 370. The pressure mechanismcomponents are displaced is external to the pouch cells and containedwithin a battery cell casing 360. The mediums 320 help ensure that auniform pressure is applied to the pouch cells when the metal plane jigsare compressed together. A pressure sensor 350 can be positioned betweenthe pouch cells or other positions within the pouch cell battery todetect a pressure being applied to the pouch cells. An externalcontroller may receive pressure values and control the pressuremechanism by, for example, controlling a motor to move the metal planejig plates toward each other or away from each other in order to achievea desired pressure applied to the pouch cells as detected by pressuresensor 350.

The pressure mechanism components of FIG. 3 are just one example ofseveral types of pressure systems that can apply pressure to the pouchcells externally from the pouch cells themselves. The pressure mechanismcomponents discussed with respect to FIG. 3 are intended to be anexample, and other implementations or variations of a pressure mechanismare considered within the scope of the present technology. Additionally,the pressure mechanism and the pressure sensor illustrated in FIG. 3 canbe implemented in instances of the pouch cell battery illustrated anddiscussed with respect to FIGS. 4-6, but are not illustrated forpurposes of simplicity and discussion.

The mediums 320 may include one layer, two layers, three layers, oradditional layers of pressure homogenizer mediums. In some instances,the mediums 320 are placed between each metal plane jig and the pouchcells closest to the plane, such that the layers of pressurehomogenizing medium are displaced between the pouch cells and the planjig. In some instances, one or more mediums may also be placed betweenone or more pairs of pouch cells.

In some instances, a pressure pattern between pouch cells can vary basedon the number of layered pressure homogenizer mediums used in a pouchcell battery. FIGS. 4A-6B illustrate different examples of pouch cellbatteries with pressure homogenizer medium configurations and pressurepatterns for each configuration.

FIG. 4A is a block diagram of a pouch cell battery with a single layerpressure homogenizer medium. As shown in FIG. 4A, pouch battery cell 400includes a plurality of pouch cells 410 and one pressure homogenizermedium layer 420 positioned between each metal plane jig and thecorresponding neighboring pouch cell. As such, there are two pressurehomogenizer medium layers in FIG. 4A.

FIG. 4B is an illustration of a pouch cell pressure pattern for thesingle-layer pressure homogenizer medium. The pouch cell pressurepattern 430 of FIG. 4B shows a fairly even distribution of pressure asshown by the discoloration 440 within the pouch cell area of pressurepattern 430.

FIG. 5A is a block diagram of a pouch cell battery with a doublepressure homogenizer medium layer. As shown in FIG. 5A, pouch batterycell 500 includes a plurality of pouch cells 510 and two pressurehomogenizer medium layers positioned between each metal plane jig andcorresponding neighboring pouch cell. Hence, pressure homogenizer mediumlayers 520 and 522 are positioned between a first metal plane jig andcorresponding neighboring pouch cell and pressure homogenizer mediumlayers 524 and 526 are positioned between a second metal plane jig andcorresponding neighboring pouch cell.

FIG. 5B is an illustration of a pouch cell pressure pattern for thedouble-layer pressure homogenizer medium. The pouch cell pressurepattern 530 of FIG. 5B shows a more even distribution (more evencompared to the pressure pattern of FIG. 4B) of pressure as shown by thediscoloration 540 within the pouch cell area within the pouch cell areaof pressure pattern 530.

FIG. 6A is a block diagram of a pouch cell battery with a triple layerpressure homogenizer medium. As shown in FIG. 6A, pouch battery cell 600includes a plurality of pouch cells 610 and three pressure homogenizermediums 620, 622, and 624 positioned between each metal plane jig andcorresponding neighboring pouch cell. Hence, pressure homogenizer mediumlayers 620, 622, and 624 are positioned between a first metal plane jigand corresponding neighboring pouch cell and pressure homogenizer mediumlayers 626, 627, and 628 are positioned between a second metal plane jigand corresponding neighboring pouch cell.

FIG. 6B is an illustration of a pouch cell pressure pattern for thetriple-layer pressure homogenizer medium. The pouch cell pressurepattern 630 of FIG. 6B shows the most even distribution (in comparisonwith pressure patterns 430 and 530) of pressure as shown by thediscoloration 640 within the pouch cell area of pressure pattern 630.

FIG. 7 is an exemplary method for pressurizing a pouch cell batteryhaving pressure homogenizing medium layers. The method of FIG. 7 may beimplemented by the system 100 of FIG. 1A or system 105 of FIG. 1B.First, a battery may be initiated at step 710. Battery initiation mayinclude applying a potential to a load and monitoring the battery by abattery management system. An initial pressure is applied to the batterypouches of the battery cell at step 720. The initial pressure may beselected based on a default value or other parameters detected by thebattery management system which is monitoring the battery cell.

The pressure applied to the battery pouches is detected within a batterycell at step 730. The pressure can be detected by a pressure sensordisplaced within the battery cell but external to the battery pouches.The pressure sensor may provide the pressure to a battery managementsystem (BMS) or a pressure controller.

The pressure between the battery pouches within a battery cell isadjusted based on the detected pressure at step 740. In some instances,if the pressure detected between the battery pouches is outside adesired range, the pressure may be adjusted to bring the pressure withinthe desired range. In some instances, the desired range of pressure is0.01 to 15 MPa. If the detected pressure is not in the desired range,the BMS or controller may control a pressure mechanism to adjust thepressure applied to the battery pouches to bring the detected pressurewithin the desired range. In some instances, metal plate jigs on eitherside of the pouch cells within the battery cell can be moved towardseach other to compress the pouches if the pressure should be increased,or the metal plate jigs within the battery cell can be moved away fromeach other if the pressure should be decreased. In some instances, theadjustment in pressure may be between 0.01-5 MPa per iteration,depending on the equipment utilized in the battery cell and the amountthe detected pressure is out of the desired pressure range.

Pressure homogenizer medium layers incorporated into the presentlydescribed battery cell have a variety of parameters. FIG. 8 is a tablewith exemplary parameters for pressure homogenizer medium layers withina pouch cell battery. As shown by table 800 of FIG. 8, the number oflayered pressure homogenizer mediums may range between one and 30. Insome instances, a battery cell having one or more battery pouches mayhave between three and four pressure homogenizer medium layers adjacentto or near each metal plane jig. The thickness of each pressurehomogenizer medium layer may range between 0.01 to 10 micrometers (mm).Each layer may have a Young's modulus ranging from 0.012 to 3.0gigapascals. The density of a pressure homogenizer medium layer mayrange between 0.1 to 2.0 g/cc. The desirable pressure range applied tothe one or more pouch cells may range between 0.01 to 15 MPa.

FIG. 9 is a computing environment for use with the present technology.System 900 of FIG. 9 may be implemented in the contexts of the likes ofbatter management system 120 and pressure controller 150. The computingsystem 900 of FIG. 9 includes one or more processors 910 and memory 920.Main memory 920 stores, in part, instructions and data for execution byprocessor 910. Main memory 920 can store the executable code when inoperation. The system 900 of FIG. 9 further includes a mass storagedevice 930, portable storage medium drive(s) 940, output devices 950,user input devices 960, a graphics display 970, and peripheral devices980.

The components shown in FIG. 9 are depicted as being connected via asingle bus 990. However, the components may be connected through one ormore data transport means. For example, processor unit 910 and mainmemory 920 may be connected via a local microprocessor bus, and the massstorage device 930, peripheral device(s) 980, portable storage device940, and display system 970 may be connected via one or moreinput/output (I/O) buses.

Mass storage device 930, which may be implemented with a magnetic diskdrive, an optical disk drive, a flash drive, or other device, is anon-volatile storage device for storing data and instructions for use byprocessor unit 910. Mass storage device 930 can store the systemsoftware for implementing embodiments of the present invention forpurposes of loading that software into main memory 920.

Portable storage device 940 operates in conjunction with a portablenon-volatile storage medium, such as a floppy disk, compact disk orDigital video disc, USB drive, memory card or stick, or other portableor removable memory, to input and output data and code to and from thecomputer system 900 of FIG. 9. The system software for implementingembodiments of the present invention may be stored on such a portablemedium and input to the computer system 900 via the portable storagedevice 940.

Input devices 960 provide a portion of a user interface. Input devices960 may include an alpha-numeric keypad, such as a keyboard, forinputting alpha-numeric and other information, a pointing device such asa mouse, a trackball, stylus, cursor direction keys, microphone,touchscreen, accelerometer, and other input devices. Additionally, thesystem 900 as shown in FIG. 9 includes output devices 950. Examples ofsuitable output devices include speakers, printers, network interfaces,and monitors.

Display system 970 may include a liquid crystal display (LCD) or othersuitable display device. Display system 970 receives textual andgraphical information and processes the information for output to thedisplay device. Display system 970 may also receive input as atouchscreen.

Peripherals 980 may include any type of computer support device to addadditional functionality to the computer system. For example, peripheraldevice(s) 980 may include a modem or a router, printer, and otherdevice.

The system of 900 may also include, in some implementations, antennas,radio transmitters and radio receivers 990. The antennas and radios maybe implemented in devices such as smart phones, tablets, and otherdevices that may communicate wirelessly. The one or more antennas mayoperate at one or more radio frequencies suitable to send and receivedata over cellular networks, Wi-Fi networks, commercial device networkssuch as a Bluetooth device, and other radio frequency networks. Thedevices may include one or more radio transmitters and receivers forprocessing signals sent and received using the antennas.

The components contained in the computer system 900 of FIG. 9 are thosetypically found in computer systems that may be suitable for use withembodiments of the present invention and are intended to represent abroad category of such computer components that are well known in theart. Thus, the computer system 900 of FIG. 9 can be a personal computer,handheld computing device, smart phone, mobile computing device,workstation, server, minicomputer, mainframe computer, or any othercomputing device. The computer can also include different busconfigurations, networked platforms, multi-processor platforms, etc.Various operating systems can be used including Unix, Linux, Windows,Macintosh OS, Android, as well as languages including Java, .NET, C,C++, Node.JS, and other suitable languages.

The foregoing detailed description of the technology herein has beenpresented for purposes of illustration and description. It is notintended to be exhaustive or to limit the technology to the precise formdisclosed. Many modifications and variations are possible in light ofthe above teaching. The described embodiments were chosen to bestexplain the principles of the technology and its practical applicationto thereby enable others skilled in the art to best utilize thetechnology in various embodiments and with various modifications as aresuited to the particular use contemplated. It is intended that the scopeof the technology be defined by the claims appended hereto.

What is claimed is:
 1. A lithium-ion battery cell having one or morepressure homogenizing medium layers, comprising: a battery casing; oneor more lithium ion pouches displaced adjacent to each other within thebattery casing; a first plane jig displaced at a first end of the one ormore lithium ion pouches and a second plane jig displaced at a secondend of the one or more lithium ion pouches; a pressure sensor displacedbetween the first plane jig and the second plane jig and detecting apressure applied to the one or more lithium ion pouches, the pressureapplied to the one or more lithium ion pouches adjusted based on thedetected pressure; and one or more pressure homogenizing medium layersdisplaced between first plane jig and the second plane jig.
 2. Thelithium-ion battery cell of claim 1, wherein the one or more pressurehomogenizing medium layers are displaced between the first plane jig anda first lithium ion pouch of the one or more lithium ion pouches nearestto the first plane jig.
 3. The lithium-ion battery cell of claim 2,wherein the one or more pressure homogenizing medium layers includethree pressure homogenizing medium layers.
 4. The lithium-ion batterycell of claim 2, wherein one or more additional pressure homogenizingmedium layers are displaced between the second plane jig and the one ormore lithium ion pouches nearest to the second plane jig.
 5. Thelithium-ion battery cell of claim 1, further comprising a controllercoupled to the pressure sensor, the controller controlling displacementof the first plane jig and the second plane jig in response to adetected pressure value output by the pressure sensor.
 6. Thelithium-ion battery cell of claim 5, wherein the controller maintainsthe pressure applied to the one or more lithium ion pouches between 0.01to 15 megapascals.
 7. The lithium-ion battery cell of claim 1, whereinthe thickness of each pressure homogenizing medium layer is between 0.01to 10 micrometers.
 8. The lithium-ion battery cell of claim 1, whereineach pressure homogenizing medium layer has a Youngs modulus of 0.01-3.0gigapascals.
 9. The lithium-ion battery cell of claim 1, wherein thedensity of each pressure homogenizing medium layer is between 0.1 and2.0 grams/cubic centimeter.
 10. A method for maintaining a homogenouspressure on battery pouches of a lithium-ion battery cell, the methodcomprising: applying an initial pressure to one or more lithium ionbattery pouches contained within a battery cell, the battery cellincluding: a first plane jig positioned near a first end of the one ormore lithium ion pouches and a second plane jig positioned near a secondend of the one or more lithium ion pouches, a pressure sensor displacedbetween the first plane jig and the second plane jig within the batterycell, and one or more pressure homogenizing medium layers displacedbetween first plane jig and the second plane jig; detecting a pressureto the one or more lithium ion battery pouches by the pressure sensor;and automatically adjusting the pressure applied to the lithium ionbattery pouches by a pressure mechanism based on the detected pressure.11. The method of claim 10, wherein the one or more pressurehomogenizing medium layers are displaced between the first plane jig anda first lithium ion pouch of the one or more lithium ion pouches nearestto the first plane jig.
 12. The method of claim 11, wherein the one ormore pressure homogenizing medium layers include three pressurehomogenizing medium layers.
 13. The method of claim 11, wherein one ormore additional pressure homogenizing medium layers are displacedbetween the second plane jig and the one or more lithium ion pouchesnearest to the second plane jig.
 14. The method of claim 10, whereinautomatically adjusting includes a controller, coupled to the pressuresensor, controlling displacement of the first plane jig and the secondplane jig in response to a detected pressure value output by thepressure sensor.
 15. The method of claim 14, wherein the controllermaintains the pressure applied to the one or more lithium ion pouchesbetween 0.1 to 10 megapascals.
 16. The method of claim 10, wherein thethickness of each pressure homogenizing medium layer is between 0.01 to10 micrometers.
 17. The method of claim 10, wherein each pressurehomogenizing medium layer has a Youngs modulus of 0.01-3.0 gigapascals.18. The method of claim 10, wherein the density of each pressurehomogenizing medium layer is between 0.1 and 2.0 grams/cubic centimeter.